Corrugated board container with interlocking flaps



CORRUGATED BOARD CONTAINER WITH INTERLOCKING FLAPS Filed June 16, 1952 lI ,/25 5 o 4 4 l 5 V INVENTOR.

Cuev- MEIFZEA/ A TTaE/VE Y5 United States Patent CORRUGATED BOARDCONTAINER WITH INTERLOCKING FLAPS Curt J. Meilzen, Wauwatosa, Wis.Application June 16, 1952, Serial No. 293,761

2 Claims. (Cl. 22936) This invention relates to a corrugated or fiberboard container with interlocking flaps.

This application is a continuation-in-part of my application Serial No.153,424, filed April 1, 1950, and entitled Corrugated Board ContainerWith Interlocking Flaps.

The object of the present invention, as in the invention described in myapplication aforesaid, is to provide a carton which is easily erectedwithout using either adhesive or staples and which has exceptionalstrength when erected, but which may be readily collapsed for shipment,storage and re-use.

In the carton of the present invention I provide an end panel whichexternally covers the interlocking tab and slot of an intermediate andinner panel. This cover feature protects the interlock from dislodgementand presents a smooth surface at the end of the carton. The inner panelin the carton of the present invention is provided with an opening and aguide tongue to receive a flap on the outer panel which is curled overthe lapping margins of the end panels. This fiap engages the tongue andextends into the opening to interlock all end panels in a multi-plystructure. The side walls of the carton are also provided with toppanels having tucking flaps which engage the tongue aforesaid to definethe closed position of the top panels and additionally interlock thecarton in erected position.

In the drawings:

Fig. 1 is a view in perspective showing a closed carton embodying thepresent invention.

Fig. 2 is a view in perspective showing the carton of Fig. l with thetop flaps and an outermost end panel open.

Fig. 3 is a fragmentary cross sectional view taken along the line 33 ofFig. 1.

Fig. 4 is a plan view on a reduced scale of the blank from which thecarton is erected.

The blank may be either of board or corrugated stock. Corrugations,where provided, desirably run continuously across the bottom and up thesides of the carton blank as shown in Fig. 4. This arrangement is suchthat when the side walls and end panels are folded into the carton, asshown in Figs. 1 and 2, the side walls and lapping end panels connectedthereto will have their corrugation disposed vertically.

The blank shown in Fig. 4 is scored upon the broken lines and slit uponthe full lines to divide the blank into panels. The side wall panels 6and 7 are joined to the bottom panel upon the score lines 8 and 9.Hinged to the top margin of each of the side wall panels is a closure 10provided at its ends with tucking flaps 11 and 12. Hinged to the bottompanel 5 upon score lines 13 and 14 are outer end panels 15 and 16,respectively.

Connected to one end of side wall panel 6 upon the score line 19 is endpanel 26 which, when the box is erected, is the innermost end panel.Panel 20 is provided with a transverse opening 21 having a transverselyelongated tongue 22 formed along the bottom margin of the opening andprojecting into the box when the panel is in erected position (see Fig.3). Panel 20 is also provided with a tab 23 formed near the outer endmargin of the panel by oblique slit 24 which runs out the bottom marginof the panel.

Side wall panel 7 is provided on score line 25 with end panel 26 whichis next adjacent inner panel 20 when the box is erected. Panel 26 isprovided near score line 25 with a transverse slot or opening 27 soformed as to receive the tab 23 of panel 20 when the end panels 20 and26 are interlocked as shown in Figs. 2 and 3. When the carton iserected, slots 27 and 21 are substantially parallel and verticallyspaced in the multi-ply end wall of the carton.

As hereinbefore indicated, panel 20 is the innermost panel, panel 26 isthe intermediate panel, and panel 15 is outermost when the carton iserected. Panels 20 and 26 are interlocked by passing tab 23 outwardlythrough slot 27 during the course of carton erection. This interlock iscovered and protected by outermost panel 15 so that only the smooth wallof the outermost panel 15 is exposed as shown in Fig. 1.

Panel 15 is further provided at its top margin with a flap 32 hingedthereto on the spaced scored lines 28 and 29. As best shown in Fig. 3flap 32 is folded over the adjacent top margins of lapping panels 20and'26 and guided by tongue 22 into the opening 21 in innermost panel20, thus further interlocking the three panels in multi-ply end wallassembly. Note that flap 32 is shouldered at 33 to reduce the width offlap 32 for its reception within the opening 21. Opening 21 is of lessextent than the width of panel 20, and its shouldered engagement withthe flap laterally restrains end wall 15.

Side walls 6 and 7 are likewise provided at their ends remote from scorelines 19 and 25, and on the score lines 34 and 35 respectively, withintermediate end panel 37 and inner end panel 36. Inner end panel 36,like inner end panel 20 aforedescn'bed, is provided with transverseopening 40 and tongue 41 connected thereto along the bottom margin ofthe opening 40 and with a tab 42. Intermediate panel 37, likeintermediate end panel 26 aforedescribed, is provided with a transverseslit 43. In the preferred embodiment the corresponding end panels 20, 36and 26, 37 are diagonally arranged "in the blank to dispose theinterlocked tabs diagonally opposite in the erected carton.

When the carton is erected the cover flaps 10 are folded to close thecarton. Tucking flaps 11 and 12 will then engage the tongues 22 and 40of the innermost end panels 20 to define the closed position of thecover as best indicated in Fig. 3. In this manner the tongues 21 and 44serve both to interlock the multi-ply end panels and cooperate withflaps 10 in retaining the top cover flaps in carton closing position.When erected the carton is firmly anchored at all parts which interlock.Because the corrugations are arranged vertically in the side and endwalls, the carton is of exceptional strength.

The outer and intermediate end panels 15, 26, 16 and 37 are alsoprovided with transverse openings indicated generally by referencecharacter 44. The inner end panels 20 and 36 are provided with likeopenings 45. Openings 44 and 45 align when the end panels are erected asshown in Figs. 2 and 3. The inner panels, however, are additionallyprovided with transversely elongated tongues 46 formed along the bottommargins of openings 45. These tongues 46 normally close the alignedopenings 44, 45, but are free of connection with the top margins of theapertures 45 to yield inwardly as shown in Fig. 3 to permit the fingersof one handling the carton to enter the carton. Thus the alignedopenings 44, 45 provide convenient hand grips. When the fingers arewithdrawn, the pressure of the carton contents will return the tongues46 to aperture closing position. The

Patented Apr. 10, 1956 multi-plyi end'wall's are sufliciently yieldableendwise to accommodate the handlers fingers in this fashion.

I claim:

1 A carton blank comprising bottom and side wali panels in; hingedconnection; first endwall panels connected toopposite ends ofthe bottompanel, second and third end wall panels" connected to" opposite ends ofre spective side wall panels and lying; laterally adjacent the first endwall panels atopposite sides thereof; the said; second and thirdwallpanels being fold'able in tapposite directions upon respective firstwall' paneis i'n carton erection to constitute three-ply carton endwalls, each secondi end wall panel having a closed ended slotadjacen-tits hinged connection withits respective side wall; panel=andgenera1ly -parailel toand adjacent the sideof} thefirst-end wall 'panelnearwhich -it lies, eachthird end wall panel being provided near itsfree end with an openended cut opening toward the side of the first endwall panel adjacent which it lies; to form atonguedirected towardtheouter end ofthe-respective first end wall panel, the saidouterend'ofeach first endlwall panel comprising a foldabl'e tab forwhich the adjacent third wall panel provides: a slot generallyparallelingand proximate to its margin remote from the first wall panel,whereby the second and third end wall panels may be lapped at oppositcends and. may be interlocked at respective diagonally-opposite lowcrc'orners of the erected carton by engaging-the tongues: of third endwall panelsin closedended slotsof second; endwall panels, the respectivefirst end wall panels being thereupon foldable outside of theinterlocked. first and second wall panels to be secured by engagement oftheir tabs through respective third wall panel-slots.

2'. A carton; comprising:- a bottom, side walls con nected therewith,and multi-ply end walls, said end walls comprising innermost andintermediate panels unitarily connectediwith the said sidewalls and anoutermost panel 7 having near its top edge av slot substantiallyparallel toconnected with said bottom, the innermost of said panels 7the carton bottom, the outermost of said panels having a flap extendingover the top of the lapping panels and engaged in said slot, saidintermediate panel having a transverse slot substantially parallel toand vertically spaced from said first mentioned slot and disposed nearthe bottom edge of said panel at a corner of the carton adjacent theconnection between the intermediate panel and the side wall, saidinnermostv panel having a tab extending downwardly through said secondmentioned slot, the portion of said tab extending beyond said-slot beingoffset from the innermost paneland confined betweennthe outer most paneland the intermediate panel, the portions of said tab connecting itsoffset portion with the innermost panel being interlocked with theintermediate panel about said second mentioned slot whereby to restrainrelative movement of the interlocked panels either in a lateral or inavertical direction, and thereby to maintain said flap againstdisplacement from said first slot.

References, Cited in the file of this patent UNITED STATES PATENTS GreatBritain Dec. 3, 193,41

